TY - JOUR
T1 - Ring nebula and bipolar outflows associated with the B1.5 supergiant Sher 25 in NGC 3603
AU - Brandner, Wolfgang
AU - Grebel, Eva K.
AU - Chu, You Hua
AU - Weis, Kerstin
N1 - Funding Information:
1Based on observations obtained at the European Southern Observatory, La Silla. 2 Astronomisches Institut der Universit‹at Wu‹rzburg, Am Hubland, D-97074 Wu‹rzburg, Germany; [email protected], [email protected]. 3University of Illinois at Urbana-Champaign, Department of Astronomy, 1002 West Green Street, Urbana, IL 61801; [email protected]. 4 Institut fu‹r Theoretische Astrophysik, Tiergartenstrasse 15, D-69121 Heidelberg, Germany; [email protected]. 5 Visiting Astronomer, Cerro Tololo Inter-American Observatory, NOAO, which is operated by AURA, Inc., under contract with the NSF.
PY - 1997
Y1 - 1997
N2 - We have identified a ring-shaped emission-line nebula and a possible bipolar outflow centered on the B1.5 supergiant Sher 25 in the Galactic giant H II region NGC 3603 (distance 6 kpc). The clumpy ring around Sher 25 appears to be tilted by 64° against the plane of the sky. Its semimajor axis (position angle ≈165°) is 6″.9 long, which corresponds to a ring diameter of 0.4 pc. The bipolar outflow filaments, presumably located above and below the ring plane on either side of Sher 25, show a separation of ≈0.5 pc from the central star. High-resolution spectra show that the ring has a systemic velocity of VLSR = +19 km s-1 and a deprojected expansion velocity of 20 km s-1, and that one of the bipolar filaments has an outflow speed of ∼83 km s-1. The spectra also show a high [N II]/Hα ratio, suggestive of strong N enrichment. Sher 25 must be an evolved blue supergiant (BSG) past the red supergiant (RSG) stage. We find that the ratio of equatorial to polar mass-loss rate during the RSG phase was ≈16. We discuss the results in the framework of RSG-BSG wind evolutionary models. We compare Sher 25 to the progenitor of SN 1987A, which it resembles in many aspects.
AB - We have identified a ring-shaped emission-line nebula and a possible bipolar outflow centered on the B1.5 supergiant Sher 25 in the Galactic giant H II region NGC 3603 (distance 6 kpc). The clumpy ring around Sher 25 appears to be tilted by 64° against the plane of the sky. Its semimajor axis (position angle ≈165°) is 6″.9 long, which corresponds to a ring diameter of 0.4 pc. The bipolar outflow filaments, presumably located above and below the ring plane on either side of Sher 25, show a separation of ≈0.5 pc from the central star. High-resolution spectra show that the ring has a systemic velocity of VLSR = +19 km s-1 and a deprojected expansion velocity of 20 km s-1, and that one of the bipolar filaments has an outflow speed of ∼83 km s-1. The spectra also show a high [N II]/Hα ratio, suggestive of strong N enrichment. Sher 25 must be an evolved blue supergiant (BSG) past the red supergiant (RSG) stage. We find that the ratio of equatorial to polar mass-loss rate during the RSG phase was ≈16. We discuss the results in the framework of RSG-BSG wind evolutionary models. We compare Sher 25 to the progenitor of SN 1987A, which it resembles in many aspects.
KW - ISM: individual (NGC 3603)
KW - Stars: evolution
KW - Stars: individual (Sher 25)
KW - Stars: mass-loss
KW - Supergiants
KW - Supernovae: individual (SN 1987A)
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U2 - 10.1086/310460
DO - 10.1086/310460
M3 - Article
AN - SCOPUS:21444449774
SN - 0004-637X
VL - 475
SP - L45-L48
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1 PART II
ER -